Load binders are well known in the field of transportation, trucking in particular. Generally, they are manually operated tools used to remove slack from link chain securing loads to flat bed trucks, semitrailers and the like. In practice, opposed ends of a chain are fastened to separate ends of the load binder. Once attached, the chain will have residual slack. The slack is removed by contracting the length of the load binder thereby creating a tension between the two loads associated with each end of the chain. Conversely, when it is desired to release the tension, the load binder may again be extended.
Two well known designs for contracting and extending a load binder include the standard lever type and the ratchet binder type. The lever type has a preset length in the contracted position and does not allow for incremental adjustments in the length. Without the opportunity to make incremental adjustments in the length, a chain is often either too tight or too loose, which can compromise the tensioning effect of the load binder and create a danger of losing the load upon an abrupt change in movement. In addition to creating a danger of losing a load, this design poses several safety risks to the user.
First, the contracted length of the load binder can be too short which results in greater tensioning of the chain than required. As the lever is pressed to a locked position, the tension created produces potential energy that is transmitted to the lever which can result in the lever snapping against the load binder or link chain. This can catch a user's fingers causing serious injury. Further, when lifting the lever to expand the load binder's length, the release of this potential energy can result in the lever flying open and striking the unsuspecting user.
The ratchet binder overcomes many of the deficiencies of the standard lever type load binder. However, it also poses some drawbacks. The standard ratchet binder uses a series of gears and threads to extend and contract it. Although this allows for incremental adjustments in the tension, it creates a rotational movement along the axis of the connection between the binder and the link chain. The rotational movement twists the link chain. The torque forces that result from the twisting action weakens and wears the link chain. Further, the threads and gears require constant lubrication, and it has been discovered that the threads wear quickly. Finally, because of the complexity of the design, the ratchet binder is much more expensive that the standard lever type.
Therefore, it is the object of this invention to provide a lever type load binder that allows for incremental adjustment in the tension applied to a load while abrogating the safety risks historically associated with the standard lever type.